There is a dire need for novel therapy for brain tumors. Diffuse glioma cell invasion into surrounding brain tissue and angiogenesis are fundamental features of gliomas that have not been successfully addressed by conventional therapy to control tumor growth in brain tumor patients. Current aggressive local treatments such as surgery, radiotherapy and chemotherapy are effective at controlling the localized mass of tumor cells in the brain. This success is only temporary, because tumor cells that have already invaded into the surrounding brain and serve as seeds by which the tumor re-grows. The process by which these tumor cells invade into the brain is not well understood. New treatment approaches that are capable to control these invading tumor cells can have a dramatic impact on patient outcome. We have developed assays in vitro and in vivo that allow us to study invading glioma and endothelial cells. Our long-term goal remains to interfere with tumor invasion and angiogenesis to diminish tumor growth. To this end we propose i) to determine mechanisms involved in the migration of both endothelial and glioma cells; and ii) to investigate the mechanism and therapeutic potential of two geldanamycin analogues on glioma in vitro and in vivo. Our proposal seeks to take advantage of new molecular biologic techniques to improve our understanding of this process. Collectively, the proposed experiments will analyze the cellular and molecular pathways necessary for tumor invasion and angiogenesis. Results from these experiments will lead to future strategies designed to inhibit specific molecular components implicated in these critical processes.